We propose to assess diagnostic and therapeutic interventions for benign prostatic hyperplasia (BPH) and localized adenocarcinoma of the prostate. Assessments will be undertaken for patients with BPH who are treated by watchful waiting, transurethral resection open prostatectomy, new medications balloon dilation, bladder neck incision, prostatotomy, transurethral incision of the prostate, and microwave diathermy. Assessments for localized adenocarcinoma of the prostate include the value of early diagnostic screening and the outcomes of treatment by watchful waiting, radiation and radial prostatectomy. In undertaking these assessments, we will (1) identify and describe use of existing and emerging technologies and characterize in detail the specific theories for efficacy advanced by their proponents; (2) identify (and, when necessary, develop measures for ) the full spectrum of outcomes that are relevant to patients. These include survival, morbidity, symptoms and functional status or quality of life: (3) build decision models that: provide a framework for evaluating the efficacy and cost-effectiveness of the alternative treatment theories, distinguish the separate importance of the probabilities for outcomes and the value or utility of these outcomes for patients, prioritize among needs for new data regarding probabilities and utilities, and provide a framework for economic analysis: (4) establish the best estimates for the probabilities of the various outcomes associated with alternative treatments (by patients subgroup), using both existing data sources as well as new data collections when necessary; (5) describe factors that predict patient's choices of therapy, understand why decisions may deviate from normative models, and develop models predicting patients satisfaction or dissatisfaction with their ultimate outcome state; (6) on a periodic basis, make results of the assessments available in suitable language and detail to help individual patients and physicians make better clinical decisions and to inform policy and resource allocation decisions.